In the 1800s, Charles Messier, a French astronomer, dedicated much of his time cataloging objects in the sky that he and other comet hunters might incorrectly identify as comets. Most of these items were deep sky objects, like nebulae and galaxies. He cataloged 103 objects in the sky, and this astronomical marathon challenges amateur astronomers to view all 110 Messier objects (7 were added to Messier’s list).
Because of our rotation around the sun and a viewer’s location on our planet, there are certain times when running this marathon is possible, and one of those times is around the March equinox, from mid-March to early-April. I seriously doubt that it would ever happen, but I would love to complete this marathon some day!
Image source: The 110 Messier objects